Question about “balanced rigs” and having all ballast unditchable

[lowviz]

@doctormike I was just about to call you a pain in the ass for your 'keep swimming' post and then you come up with the above.

*sigh*

 

[CT-Rich]

Ditch breathing Gas? Hmmm... why might I find my self low in the water and think “hey, let me get rid of all this air...”. Or maybe the problem is the air in the tank isn’t on? By the way, how long will you tread water while bleeding down my steel 120?

Second option.... let me take my $2,000 of gear and drop that... because money isn’t so important....

Third option, let me drop these two $50 pouches a long with the $30 dollars of lead...

 

[lowviz]

Too complicated, I like a W/B. One step, not two.

 

[doctormike]

@doctormike I was just about to call you a pain in the ass for your 'keep swimming' post and then you come up with the above.

*sigh*

I'm still a pain in the ass.

 

[CWK]

I would never dump gas from a tank while still in the water. Yes, gas weighs something. But the kind of scenario that would make dumping gas weight a consideration would be just the sort of scenario where you would want all the gas you had. Are you thinking exhausted diver on the surface with a blown wing, nothing else to ditch, and an overweighted rig? The minute your head goes underwater, you don't want an empty tank...

I'm positively buoyant in sea water with or without my wetsuit. The only reason I'd be slightly negative with a full tank of air is because weights and full tank are negative. With a blown wing/BCD I'd be left with three options to establish positive bouyancy - make the tank positive, dump the rig, or inflate SMB. In my last tech course, the material talks about carrying 2 SMBs and I did carry 2 SMBs on all dives. That's about 100lb of lift and is more than enough. As this is the basic forum, consider 1 SMB with about 50lbs of lift a necessary piece of kit.

 

[lowviz]

You are kidding, right?

How about you suck your tank down to zero and then continue to descend. Water fills a third of your tank through the reg. Is that a problem?

 

[doctormike]

I'm positively buoyant in sea water with or without my wetsuit. The only reason I'd be slightly negative with a full tank of air is because weights and full tank are negative. With a blown wing/BCD I'd be left with three options to establish positive bouyancy - make the tank positive, dump the rig, or inflate SMB. In my last tech course, the material talks about carrying 2 SMBs and I did carry 2 SMBs on all dives. That's about 100lb of lift and is more than enough. As this is the basic forum, consider 1 SMB with about 50lbs of lift a necessary piece of kit.

Right. And my point was that of the three options, dumping gas is the bad one.

 

[CWK]

No need to suck down to zero. If you have a burst tank o ring and the tank fills with water as you swim to the surface, you can fill your SMB to establish positive buoyancy, but if that fails then dump the rig.

 

[CWK]

Right. And my point was that of the three options, dumping gas is the bad one.

Perhaps you are right that it may not he the optimum solution, but it is one of the three alternatives.

 

[CT-Rich]

All right, this is the basic scuba forum, so let's try to deal with single tank, NDL diving for a little while. When PADI revised its standards a few years ago, part of the impetus was a study of dive fatalities. One of the things they found was that some single tank divers had successfully reached the surface in an OOA situation, been unable to fill their BCDs because of the OOA situation, been unable to stay on the surface, sank, and drowned. As a result, they put a greater emphasis on manual inflation of the BCD, and they added dropping weights on the surface.

But let's look at the situation a little further.

A weight check is typically done by dumping all air from the BCD while holding a normal breath. If you are properly weighted, you should float at eye level when you are not kicking. This is usually done with a full tank. Some people say to add enough weight to compensate for the loss of the weight of the air during the dive, but others say it is not necessary because of trapped air at the beginning of the dive. At any rate, the key idea is this: a properly weighted diver with an empty tank should float at least at eye level while making no effort whatsoever to stay afloat. A properly weighted diver with an empty tank should have a very hard time submerging. That diver should have no trouble staying afloat with an empty BCD and minimal kicking. A single tank diver who cannot stay at the surface with an empty tank is significantly overweighted.

I totally agree with the you should be properly weighted argument, but let’s face it, how often do you do a weight check? I get weights dialed in , but then decide to take a light and camera or ditch the hood and gloves or I forgot something and just leave it’s good enough.

People seem pretty cool with idea of ditch their rigs. Maybe they coulda attach some thing cheap to their rigs, so like could drop that excess weight and keep all th safety gear like mirrors and whistles and SMB andbreathing gas with them on the surface...

We could Patent it and make a ton of money. What could we call this cool disposable stuff that save divers their equipment?